Destroying insects with halogen substituted alkenylthioalkyl esters of phosphorus acids



3,080,276 Patented Mar. 5, 1963 assignor to Monsanto 'a corporation ofThis invention relates to a new class of organo phosphorus compounds,insecticidal compositions containing them and to methods of destroyinginsects. More particularly, the invention relates to halogen substitutedalkenylthioalkyl esters of phosphorus acids, especiallyphosphorothioates.

The new compounds may be conveniently represented by the general formulaIl -O X Rz-O where R and R are hydrocarbon radicals, preferably loweralkyl radicals, X and X are oxygen or sulfur, at least one preferablybeing sulfur, A is an alkylene radical, preferably methylene, and R is ahalogen substituted alkenyl radical. Examples of R and R are methyl,ethyl, propyl, isopropyl, butyl, isobutyl, sec. butyl, amyl, isoamyl,allyl, phenyl, cyclohexyl, hexyl, octyl and decyl.

The radicals designated R may be selected from a variety of halogensubstituted alkenyl radicals but is preferably a halogen substitutedlower alkenyl group, as for example 2-chloroallyl, 2-bromoallyl,3-chloroallyl, 3- iodoallyl, 2-fiuoro-3-choroallyl, 3-bromo-2-buteny1,3- chloro-Z-butenyl, 2,3-dichloroallyl, 3,3-dichloroallyl, 2,3-dichloro-Z-butenyl, 2,3-diodo-2-butenyl, 2,3-dichloro-4- brornobutenyland 2,3,3-trichloroallyl.

While the new compounds are particularly valuable systemic insecticides,they have other uses. Thus they comprise useful mineral oil adjuvants inwhich they serve as antioxidants and to increase the load carryingcapacity of mineral oil lubricants. The method of synthesis can vary ashereinafter described. The invention will be fully understood andapparent from the detailed examples which follow:

EXAMPLE 1 Into a suitable reactor is charged 15.7 grams (0.10 mole) of2-chloroallyl thiomethyl chloride, 22.3 grams (0.11 mole) of ammonium0,0-diethyl phosphorodithioate and 100 ml. of acetone and the mixturerefiuxed for 4 hours. After cooling, the precipitated ammonium chlorideis filtered and the salt cake washed with acetone. The filtrate is thenstripped of acetone under vacuum, washed with Water and taken up inmethylene dichloride. The methylene dichloride solution is washed withwater and then stripped to 100" C./5 mm. The 0,0-diethylS-(2-chloroallylthiomethyl)phosphorodithioate remains as an amber liquidin 96.0% yield. Analysis: 9.8% phosphorus, 11.9% chlorine and 31.3%sulfur as compared to 10.1% phosphorus, 11.6% chlorine and 31.4% sulfurcalculated for C H ClO PS EXAMPLE 2 Substituting 20.6 grams (0.11 mole)of ammonium 0,0-diethyl phosphorothioate for the phosphorodithioate inthe procedure of Example 1, 0,0-diethylS-(2-chloroallylthiomethyl)phosphorothioate is obtained as an amberliquid in 93.0% yield. Analysis: 9.9% phosphorus and 22.0% sulfur ascompare-d to 10.6% phosphorus and 22.0% sulfur calculated for C H ClO PSOther examples prepared by the same procedure as in Example 1 butsubstituting the appropriate reactants are summarized in tabular formbelow. All are amber oils.

Table 1 Analysis, percent Product Calcd. Found 0, O-DiethylS-(3,3-dichloroallylthiomcthyl)phosphorodithioate.

0, O-Diethyl S-(3,3-dichloroallylthiomethyl)phosphorothioate.

0,0-Diethyl S-(3-ehloroallylthiomethyl) phosphorodithioate.

0,0-Dietnyl S-(3-chl0roallyltliiomethyl) phosphorothioate.

O, O-Dimethyl S-(3-chloroallylthiomethyl)phosphorodithioate.

0,0-Diisopropyl S-(Zi-ehloroallylthiomethyl)phosphorodithioate.

ate. 0,0-Dimethy1 S-(Z-chloroallylthiomethyl)phosphorodithioate.

O, O-Dimethyl S-(3,3- 1ichloroallylthiomethyl)phosphorodithioate.

0, O-Dimethyl S-(3-ehloro-2-butenylthiornethyl)phosphorodlthioate.

EXAMPLE 14 A mixture of 15.2 grams (0.1 mole) of2-(2-chloroallylthio)ethanol, 19.7 grams (0.1 mole) of 0,0-diethylphosphorochloridothioate, 10.1 grams (0.1 mole) of triethylamine and 100ml. of benzene is prepared and the mixture heated at refluxingtemperature for 4 hours in the presence of 0.2 gram of finely dividedcopper powder. The salt cake is filtered, washed with benzene and thefiltrate and washings combined to be subsequently Washed with 3% sodiumcarbonate solution, then twice with successive water Washes. The solventis stripped off to yield as the residue 0,0-diethylO-2-(2-chloroallylthio)ethyl phosphorothioate as a mobile liquid.

EXAMPLE 15 Substituting 0.1 mole of diethyl phosphorochloridate fordiethyl phosphorochloridothioate in the foregoing procedure yieldsdiethyl 2-(2-chloroallylthio)ethyl phosphate.

EXAMPLE 16 A mixture of grams (0.43 mole) of 0,0-diethylphosphorodithioic acid and 47.0 grams (0.43 mole) ofZ-chloroallylmercaptan is prepared and 38 grams (0.46 mole) of 37%aqueous formaldehyde added during 45 minutes. The reactants are stirredfor about 3 hours Without heating and then stirred at about C. for 3hours longer. The product is separated from the water layer, washedtwice with water and stripped of volatiles by heating on a steam bath invacuo. The residue, 0,0- diethy]S-(2-chloroallylthiomethyl)phosphorodithioate is an amber liquid.

EXAMPLE 17 A mixture of 17.1 grams (0.10 mole) of 2--chloroallylthioethyl chloride, 22.3 grams (0.11 mole) of ammonium QO-diethylphosphorodithioate and ml. of acetone 18 prepared and the mixturerefluxed for 4 hours. After cooling, the precipitated ammonium chlorideis filtered and the salt cake washed with acetone. The filtrate is 8then stripped of acetone under vacuum, washed with water and taken up inmethylene dichloride. The methylene dichloride solution is washed withwater and then stripped to 100 C./S mm. The 0,0-diethyl S-(Zchloromlylthioethyl)phosphorodithioate remains as an amber-liquid.

EXAMPLE 18 Substituting 20.6 grams (0.11 mole) of ammonium 0,0-diethylphosphorothioate for the phosphorodithioate inthe procedure of'Examplel7, 0,0-diethyl S-(Z-chloroallylthioethyl)phosphorothioate is obtainedas a dark amber liquid.

The new compounds are useful for destroying a variety of insect pests bycontacting the insect in its environment either directly or indirectlythrough translocation within the plant. Thecompounds may be applied insolution, emulsion, water dispersion or as a dust formulation whereinthe active ingredient is distributed over a dry, ireedlowing powder, asfor example clays, including bentonite and attapulgite, or suchmaterials as talc, diatomaccnus earth, fullers earth, chalk or calciumcarbonate. Although most of the toxicants are insoluble in water, theyare soluble in common organic solvents. hey may be dispersed directly inwater or a solution in an organic solvent emulsified in aqueous mediumby the aid of a dispersing agent. As dispersing and wetting agents theremay be employed soft or hard sodium or potassium soaps, alkylatedaromatic sodium sulfonate, such as sodium dodecylbenzene sulfonate, anamine salt, as for example dibutylammonium dodecylbenzene sulinnate,alkali metal salts of sulfated fatty alcohols, ethylene oxidecondensation products of alkyl phenols, or tall.

pounds. Sprays for application to agricultural crops may suitably beapplied at concentrations of 0.001-1.0%. An acetone solution of0,0-diethyl S-(2-chloroallylthiomethyl)phosphorodithioatc applied as aresidual treatment to filter paper at a rate of 1 mg. per square footgives 100% kill of the red flour beetle (Tribolium castaneum). Kills of100% are also obtained from acetone solutions of 0,0-diethylS-(2-chloroallylthiomethyl)- phosphoroethioate applied at the rate of 5mg. per square foot. Likewise 100% kill of mosquito larvae (Aedesaegypti) is obtained with 0,0-dimethyl S-(3-chloro-2-butenylthiomethyl)phosphorodithioate at a concentration of 0.04 ppm. Thetest involves dissolving the compound in acetone, adding sufficientdistilled water to an aliquot of this solution to provide 25 cc. havinga concentration of0.04 ppm. of the compound, transferring about 25mosquito larvae to a test tube containing the aforesaid 25 cc. mass,stoppering the test tube, and holding the test tube for 43 hours at roomtemperature. Other insects to which the compounds. are extremely toxicinclude southern armyworm (Prodenis eridam'a) and plum curculio(Conotrachelus nenuphar).

Systemic activity is demonstrated by immersing excised stems of beanplants in emulsions of the chemicals for 3 days. The leaves are then cut05, infected with the chosen insects and percent kill noted after 48hours. In emulsions at concentrations of 0.1% and even at 0.001% orlower, high percent kills are noted against such insects as two-spottedmite (Tetranychus telarius), Mexican bean beetle (Epilachna varivestis)and cotton aphid (Aphis g op o- It is intended to cover all changes andmodifications of the examples of the invention herein chosen forpurposes of disclosure which do not constitute departures from thespiritand scope of the invention.

This application is a continuation-impart of applicaspacers tion SerialNo. 757,124, filed August 25, 8, now Patent No. 3,020,305.

What is claimed is: 1. An insecticidal composition comprising as theessentim active ingredient a compound of the structure Rr-O X P-XAS-RRr-O wherein R and R each represent a lower alltyl radical, X and Xrepresent a chalkogen having atomic weight less than 40, A represents alower alkylene radical and R represents a halogen substituted lowerZ-alkenyl radical.

2. An insecticidal composition comprising as the essential activeingredient a compound of the structure P-X(CH2) B ""R Rz-O where R and Rrepresent lower allcyl, X and X represent a chalkogen having atomicWeight less than 40, n represents an integer at least 1 but less than 3and R represents a halogen substituted allyl radical.

3. An insecticidal composition comprising as the essential activeingredient a compound of the structure R O\fi P--S-CH2-S-R Rr-O whereinR and R each represent a lower aliryl radical and R is a halogensubstituted allyl radical.

4. An insecticidal composition comprising as the essential activeingredient a compound of the structure R1O\fi P-S-GH:-S-R

wherein R and R each represent a lower alkyl radical and R is a halogensubstituted allyl radical.

5. An insecticidal composition comprising as the essential activeingredient a compound of the structure wherein R and R each represent alower alltyl radical and R is a halogen substituted allyl radical.

6. An insecticidal composition comprising as the essential activeingredient 0,0-dimethyl S-(3,3-dichloroallylthiomethyl phosphorodithioate.

7. An insecticidal composition comprising as the essen tial activeingredient 0,0-dimethyl S-(3-chloro-2-butenylthiomethyl)phosphorodithioate.

8. The method of destroying insects which comprises bringing the insectinto contact with a compound of the structure Rr-O wherein R and R eachrepresent a lower alkyl radical, X and X represent a chalkogen havingatomic weight less than 40, A represents a lower alkylene radical and Rrepresents a halogen substituted lower Z-alkenyl radical.

9. The method of destroying insects which comprises bringing the insectinto contact with a compound of the structure RLO\}H P-X(CHz)nS-R Rz-Owhere R; and R represent lower alkyl, X and X repre- 5 sent a chalkogenhaving atomic weight less than 40, n represents an integer at least v1but less than 3 and R represents a halogen substituted allyl radical.

10. The method of destroying insects which comprises bringing the insectinto contact with a compound of the structure wherein R and R eachrepresent a lower alkyl radical and R is a halogen substituted allylradical.

11. The method of destroying insects which comprises bringing the insectinto contact with 0,0-dimethy1 S-(3,3- dichloroallylthiomethylphosphorodithioate.

12. The method of destroying insects which comprises 6 bringing theinsect into contact with 0,0-dimethy1 S-(3chloro-2-butenylthiomethyl)phosphorodithioate.

References Cited in the file of this patent UNITED STATES PATENTS2,661,366 Garnrath et a1. Dec. 1, 1953 2,678,329 Gamrath et al May 11,1954 2,786,009 IPianfetti et a1 Mar. 19, 1957 2,861,912 Sallman Nov. 25,1958 FOREIGN PATENTS 1,113,363 France Dec. 5, 1955 795,340 Great BritainMay 21, 1958 OTHER REFERENCES Clark et al.: J. Agr. Food Chem., vol.III, pp. 834- 6 (1955).

8. THE METHOD OF DESTROYING INSECTS WHICH COMPRISES BRINGING THE INSECT INTO CONTACT WITH A COMPOUND OF THE STRUCTURE 